1st. Generation .45 SSA Transition from Screw to Spring Loaded Screw For Base Pin?

[UtopiaTexasColt45]

I was watching a YouTube short by Hickock45 where he showed a first generation .45 SSA with a screw into the frame to hold the base pin in place vs the spring loaded screw used later on. He stated that the screw into the frame indicated a SSA frame for black powder cartridges where as the spring loaded base pin lock indicated a frame for smokeless powder cartridges. What year and at what serial number was this change made? Thanks...

[Old-Colts]

This isn't a real straight forward subject because we have Standard Frame, Standard Frame Target Model (Flattop), and Bisley Models to consider; but I will assume you are referring to Standard Frame Single Actions. The short answer is the change from screw to spring loaded base pin release occurred somewhere near serial number 164100. However, that has nothing to do with smokeless vs. black powder. Single Actions really weren't safe for use with smokeless powder until somewhere near the 190000 serial number range.

[1873Bob]

The transverse latch was introduced 1892 but did not become prevalent until 1896 at about serial 164000. As the above poster mentions and what I have read from various authorative journals the
SAA revolvers below serial 192000 should be treated and shot with BP loads only. Above that they will handle smokeless.